dilate.owin {spatstat}R Documentation

Dilate a Window

Description

Perform morphological dilation of a window

Usage

 dilation.owin(w, r, ..., polygonal=TRUE, tight=TRUE)
 dilate.owin(w, r, ..., polygonal=TRUE, tight=TRUE)

Arguments

w A window (object of class "owin".
r positive number: the radius of dilation.
... extra arguments to as.mask controlling the pixel resolution, if the pixel approximation is used.
polygonal Logical flag indicating whether to compute a polygonal approximation to the erosion (polygonal=TRUE) or a pixel grid approximation (polygonal=FALSE).
tight Logical flag indicating whether the bounding frame of the window should be taken as the smallest rectangle enclosing the dilated region (tight=TRUE), or should be the dilation of the bounding frame of w (tight=FALSE).

Details

The morphological dilation of a set W by a distance r > 0 is the set consisting of all points lying at most r units away from W. Effectively, dilation adds a margin of width r onto the set W.

The functions dilate.owin and dilation.owin are identical, and compute the dilation of the window w.

If polygonal=TRUE and w is a rectangle or a polygonal window, then a polygonal approximation to the dilation is computed.

Otherwise, the window w is first approximated by a binary pixel image, and the arguments "..." are passed to as.mask to determine the pixel resolution. There is a sensible default.

Value

Another object of class "owin" representing the dilated window.

Author(s)

Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz

See Also

erode.owin for the opposite operation.

owin, as.owin

Examples

  w <- owin(c(0,1),c(0,1))
  v <- dilate.owin(w, 0.1) 

[Package spatstat version 1.16-0 Index]